Throttle system

Abstract

Engine air flow is controlled by principal and supplementary throttles--the principal throttle being positioned by a stepper motor but also having a mechanical linkage to assure at least partial throttle opening when required, and the supplementary throttle being positioned by a mechanical linkage to permit primary control of engine output by the principal throttle while assuring that engine output is minimized when required.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. A throttle system for controlling air flow through an engine air induction passage, said throttle system comprising principal and supplementary throttle valves disposed in series in said induction passage, each of said valves being rotatable from a closed position through partially open positions to a wide open position, a principal lever secured to said principal valve and a supplementary lever secured to said supplementary valve, a command lever rotatable from a minimum engine output command position through partial engine output command positions to a maximum engine output command position, electronically controlled means connected to said principal lever and at least at times responsive to rotation of said command lever from one engine output command position to another engine output command position for rotating said principal valve from a position corresponding to said one engine output command position to a position corresponding to said another engine output command position, means adapted to mechanically link said command lever and said principal lever for assuring rotation of said principal valve from its closed position to at least a partially open position in response to rotation of said command lever from a partial engine output command position to its maximum engine output command position, and means mechanically linking said command lever and said supplementary lever for rotating said supplementary valve from its closed position to its wide open position in response to rotation of said command lever from its minimum engine output command position to a partial engine output command position.